Forming method for single crystal diamond tools based on focused ion beam

Abstract

The present invention provides a forming method for a single crystal diamond tool based on a focused ion beam, and the specific steps are as follows: a plasma focused ion beam with Xe ions as an ion source is used to etch the rake face, the flank face and the side face of the single crystal diamond tool; a large beam is used to rough the side face to obtain a side face with a step profile defect; the flank face is roughed, and the flank face to be processed and the rough-machined side face have a back angle of 6°-8° through manual compensation; the rake face is rough-finished to obtain a rake face with a negative rake angle of 20°; the side face is fine-machined using a small beam; the flank face is fine-machined to obtain a flank face with 6°-8°; and then different small beams are used to process the cutting edge to obtain a single crystal diamond tool with a certain hardness cutting edge. The processing cycle of the present invention is shorter than that of mechanical polishing, and there is no need to consider the processing temperature during processing. The processed diamond tool has certain cutting performance and more accurate geometric dimensions.

Description

Technical Field

[0001] The invention relates to the technical field of tool processing, and in particular to a forming method for a single crystal diamond tool based on a focused ion beam. Background Art

[0002] Diamond tools have excellent properties such as high hardness, good wear resistance, good thermal conductivity, low friction coefficient and low thermal expansion coefficient, and are often used in difficult-to-process materials and ultra-precision cutting fields. The accuracy and efficiency of diamond tools under high-speed cutting are well guaranteed. The excellent performance of diamond tools themselves depends on the performance of single-crystal diamond materials. In the microscopic view of diamond materials, each carbon atom forms a covalent bond with the four surrounding atoms; in space, it presents a regular tetrahedral structure. Under this structure, the bonding force between atoms is strong, so the hardness is extremely high on the macroscopic view, which reflects the characteristics of extremely high hardness of the tool.

[0003] There are many processing methods for diamond tools nowadays. The processing technology of single crystal diamond tools is generally mechanical polishing, which has the advantages of simple operation, high precision and high efficiency. Laser sintering has the advantages of short processing cycle and can process difficult-to-process materials, but each method also has defects. The anisotropy of single crystal diamond will have a great impact on the grinding of mechanical polishing, and the impact on the cutting edge is extremely obvious; mechanical polishing can produce extremely sharp tool edges, but the production cycle of tools is too long, and there are certain uncertainties in the polishing process, which may extend the production cycle due to chipping; and laser sintering processing of tools, due to the characteristics of the laser beam itself, although the production cycle is short, it cannot produce sharp diamond tools, and is suitable for rough processing of tool forming.

[0004] The focused ion beam first used liquid metal gallium as the emission material because gallium has a low operating temperature, and liquid gallium is extremely difficult to volatilize, has a heavy nucleus, has good adhesion to tungsten needles, and has good oxidation resistance. In contrast, the Xe ion source uses high-frequency vibration to ionize the inert gas, and then extracts and focuses the ion beam through the extraction electrode. Unlike the liquid Ga ion source, the maximum beam current of the ion beam of the Xe plasma source after passing through the aperture to reach the sample can reach 2uA, which significantly improves the micro-area processing capability of the FIB and can reach 50 times the processing speed of the liquid Ga ion FIB. Therefore, it has higher practicality and the processing size often reaches hundreds of microns.

[0005] Currently, there is a need for a tool forming method that can quickly produce a tool that meets cutting requirements, and the processing of conventional-sized single-crystal diamond tools is rarely used in the ion beam direction. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides a forming method for a single crystal diamond tool based on a focused ion beam, which uses a plasma focused ion beam with Xe ions as an ion source to perform etching, rough machining and fine machining on the front blade, back blade and side blade of the single crystal diamond tool, respectively, and controls the required edge degree of the blade with different angles by adjusting the ion beam intensity of the beam energy in the plasma focused ion beam, reduces the chipping of the cutting edge, improves the sharpness of the tool edge, and thus produces a single crystal diamond tool with a certain hardness edge. The processing cycle of the present invention is shorter than that of mechanical polishing, and there is no need to consider the processing temperature during processing. The processed diamond tool has certain cutting performance and more accurate geometric dimensions.

[0007] The present invention provides a forming method for a single crystal diamond tool based on a focused ion beam, and the specific implementation steps are as follows:

[0008] S1. Etching the single crystal diamond tool: etching the rake face, flank face and side face of the single crystal diamond tool using a plasma focused ion beam with Xe ions as an ion source;

[0009] S2. Rough machining of the side cutting edge of the single crystal diamond tool: fix the single crystal diamond tool obtained in S1 on a sample stage with its upper surface facing upward, and use a plasma focused ion beam to perform rough machining on the side cutting edge of the single crystal diamond tool to remove material, thereby obtaining a side cutting edge with a step-shaped profile defect;

[0010] S3. Rough machining of the back face of the single crystal diamond tool: According to the characteristics of the single crystal diamond tool, the angle between the plasma focused ion beam and the workbench is adjusted. Considering that the energy distribution will cause machining defects when the beam current is large, the inclined side wall will be generated, and the angle is manually compensated by ±1° so that the back face to be machined and the side face after rough machining have a back angle of 6°-8°. The expression of the ion beam intensity of the beam energy in the plasma focused ion beam is:

[0011]

[0012] Wherein, J is the ion flow concentration at the processing position during plasma focused ion beam processing, I is the beam size during plasma focused ion beam processing, σ is the standard deviation, and x and y are the corresponding coordinate positions on the processing surface when the processing center position is (0.0);

[0013] S4. Rough-machining and fine-machining the front cutting edge of the single crystal diamond tool respectively: placing the upper surface of the material of the single crystal diamond tool vertically upward on the sample table, rotating the sample table around the workbench to 52 degrees, etching a shallow groove at the edge of the cutting edge of the processed single crystal diamond tool, and then mounting the single crystal diamond tool with the front cutting edge facing upward on the auxiliary ramp, and turning the auxiliary ramp around the fixed axis T of the equipment at a certain angle to obtain a front cutting edge with a negative front angle of 20°;

[0014] S5. Finishing the side cutting edge of the single crystal diamond tool: Fix the upper surface of the single crystal diamond tool material downward on the auxiliary inclined table, and use the nA-level small beam flow of the plasma focused ion beam to fine-tune the position of the cutting edge until there is no obvious surface damage. In the process, the step defects generated by the rough machining will be neutralized to improve the efficiency;

[0015] S6. Finishing the back face of the single crystal diamond tool: fix the single crystal diamond tool material with the upper surface facing downward on the auxiliary ramp, and flip the auxiliary ramp 4°-6° around the fixed axis T of the equipment to obtain a back face with an angle of 6°-8°; then use a small beam of 60nA and a small beam of 15nA to perform primary and secondary processing on the cutting edge of the single crystal diamond tool respectively to obtain a single crystal diamond tool with a certain hardness cutting edge.

[0016] Preferably, in step S1, the plasma focused ion beam is based on the sputtering yield of Sigmund theory, and the expression of the linear chain collision model of the sputtering yield of Sigmund theory is:

[0017]

[0018]

[0019]

[0020]

[0021] Among them, M1 and M2 are the relative atomic masses of the incident ions and the target material, Z1 and Z2 are the atomic numbers of the incident ions and the solid target material atoms, and Y is the sputtering yield. E s is the surface binding energy of the solid target, S n is the nucleus stopping cross section, θ is the incident angle of the ion beam, E represents the energy generated, and ε is the reduced energy, that is, the ratio of the backscattered electron energy to the incident electron energy.

[0022] Preferably, in step S2, the expression for removing material in the rough machining is:

[0023]

[0024] Wherein, W is the removal amount of the single crystal diamond tool, m is the relative atomic mass of the atoms of the single crystal diamond tool, I is the beam current of the focused ion beam (FIB), and t is the sputtering time of the plasma focused ion beam.

[0025] Preferably, in step S3, the manual compensation angle is 1°-4°.

[0026] Preferably, in step S4, the shallow groove has a length of 50 μm-100 μm, a depth of 0 μm-1 μm, and a distance between the shallow groove and the edge of the cutting edge of the processed single crystal diamond tool is 150 μm-250 μm.

[0027] Preferably, in step S4, the inclination angle of the auxiliary ramp is 40°.

[0028] Preferably, in step S6, when secondary processing is performed with a small beam current of 15 nA, the edge region with weaker beam energy distribution in the plasma focused ion beam needs to be processed at a distance of 50 nm-100 nm from the edge region at the cutting edge.

[0029] Preferably, a large beam current of μA level is selected for rough machining, and a small beam current of nA level is selected for fine machining, and the acceleration voltage for the rough machining and the fine machining is 30 kV.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. The forming method of the present invention does not need to consider the isotropy of single crystal diamond, the edge processed is sharper than that processed by laser, and the processing cycle is shorter than that of mechanical polishing.

[0032] 2. The present invention ignores the processing temperature during conventional tool processing, and the large-sized diamond tool processed has certain cutting performance and more accurate geometric dimensions.

[0033] 3. The present invention uses Xe ion source to process large-sized micro-tools, which is a new large-sized micro-tool preparation process that has not appeared in the current focused ion beam based diamond tool processing. Compared with the existing patents for processing diamond tools with focused ion beams, this patent does not need to borrow other auxiliary devices such as mechanical rotating arms, but uses a tilting table with auxiliary angles to compensate for the angle, and the processing steps are more concise, and the processing defects can also be reasonably offset. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a flow chart of a forming method for a single crystal diamond tool based on a focused ion beam;

[0035] Figure 2a-2eThe figure is a practical processing flow chart of the forming method for single crystal diamond tool based on focused ion beam of the present invention;

[0036] Figure 3 This is a tool edge and tool overview image taken using a SEM in a forming method for a single crystal diamond tool based on a focused ion beam according to the present invention;

[0037] Figure 4 This is a diagram showing the edge measurement results of a tool edge after machining using a white light interferometer in a forming method for a single crystal diamond tool based on a focused ion beam of the present invention;

[0038] Figure 5a-Figure 5b This is a diagram of the processed surface of Cu after processing in the forming method for single crystal diamond tools based on focused ion beam of the present invention.

[0039] Figure 6 This is a simplified internal processing diagram drawn based on the focused ion beam processing principle of the present invention.

[0040] Main reference numerals:

[0041] Material upper surface 1, front cutting edge 2, material lower surface 3, back cutting edge 4, electron beam emission port 5, ion beam emission port 6, 40° inclined platform 7, T-axis rotation direction 8. DETAILED DESCRIPTION

[0042] In order to fully describe the technical content, objectives and effects of the present invention, the following will be described in detail with reference to the accompanying drawings.

[0043] The forming method for a single crystal diamond tool based on a focused ion beam of the present invention is as follows: first, the surface of the single crystal diamond tool is polished to obtain a relatively smooth surface, and a processing method combining roughing and finishing is adopted, and a focused ion beam of a Xe ion source is used for large beam processing, and the rough processing determines the preliminary outline of the single crystal diamond tool. Since the surface quality and the cutting edge are far from meeting the requirements for the use of the tool, serious processing defects such as inclined side walls will be generated when large beam processing is performed, and the reason is that the beam energy distribution of the focused ion beam is Gaussian distribution, and the closer to the center of the beam spot, the greater the relative number of ions. Here, due to different ion sources and different processing parameters, different inclination angles will appear when processing different materials and different depths. The verticality is ensured by manually compensating the angle method when the front blade face and the side blade face are processed according to the influence of different parameters on the angle by pre-processing the material. After the verticality and horizontality are guaranteed, the disadvantage of the curtain structure will be particularly obvious under high beam current, so it is necessary to use a small beam current to correct the surface and the cutting edge for fine processing, reduce the influence of processing defects, reduce the processing traces on the surface and improve the sharpness of the cutting edge.

[0044] like Figure 1As shown in Figure 2, the specific implementation steps are implemented as follows:

[0045] S1. Etching the single crystal diamond tool: etching the front cutting surface 2, the back cutting surface 4 and the side cutting surface of the single crystal diamond tool using a plasma focused ion beam with Xe ions as an ion source.

[0046] Specifically, the plasma focused ion beam is a sputtering yield based on Sigmund's theory. The linear chain collision model of the sputtering yield of Sigmund's theory is expressed as:

[0047]

[0048]

[0049]

[0050]

[0051] Among them, M1 and M2 are the relative atomic masses of the incident ions and the target material, Z1 and Z2 are the atomic numbers of the incident ions and the solid target material atoms, and Y is the sputtering yield. E s is the surface binding energy of the solid target, S n is the nucleus stopping cross section, θ is the incident angle of the ion beam, E represents the energy generated, and ε is the reduced energy, that is, the ratio of the backscattered electron energy to the incident electron energy.

[0052] Furthermore, the sputtering yield indicates the number of target atoms removed by a single incident ion. Since the atomic numbers of Xe ions and Ga ions are 54 and 31, respectively, and their atomic weight values ​​are 131.2 and 69.72, respectively, the target element C is simulated and calculated by comparing the sputtering yields of Ca ion source and Xe ion source, and it is found that the sputtering yield of Xe ions is about 5 times that of Ga ions. Therefore, this patent uses a Xe ion source to process large-scale single-crystal diamond tools.

[0053] S2. Rough machining of the side cutting edge of the single crystal diamond tool: fix the material upper surface 1 of the single crystal diamond tool obtained in S1 on the sample table with the upper surface 1 facing upwards. Since the direction of the electron beam emitted by the electron beam emitting port 5 is perpendicular to the plane of the workbench and the angle between the direction of the ion beam emitted by the ion beam emitting port 6 and the workbench is fixed at 52°, the side cutting edge of the single crystal diamond tool is rough machined to remove material using a plasma focused ion beam using Xe ions as the ion source. A large beam current of 2.5 μA and an acceleration voltage of 30 kV are selected to obtain a side cutting edge with a stepped plane but with a contour.

[0054] Preferably, the amount of material removed during roughing is based on the following expression:

[0055]

[0056] Among them, W is the removal amount of the single crystal diamond tool, m is the relative atomic mass of the single crystal diamond tool atom, I is the beam current of the focused ion beam (FIB), and t is the sputtering time of the plasma focused ion beam, so as to calculate the ratio of the removal amount to time.

[0057] According to this formula, when processing a 500μm single-crystal diamond tool, Xe ions should be used for large beam processing. At the same time, when processing the same volume of target material, a shorter processing time will be used.

[0058] S3. Rough machining of the back face 4 of the single crystal diamond tool: According to the material and machining speed of the single crystal diamond tool, adjust the angle between the plasma focused ion beam and the worktable. Considering that the energy distribution will cause machining defects when the beam is large - inclined side walls, it is necessary to manually compensate 1°-4° so that the machining direction of the plasma focused ion beam is 88° with the two directions of the machining surface instead of vertical machining. When machining the back face 4 of the single crystal diamond tool, it is necessary to flip around the fixed T-axis rotation direction 8 to 45° so that the back face 4 is machined with a back angle of 7°, so that the back face 4 to be machined and the side face after rough machining have a back angle of 6°-8°. The compensation angle is related to the machining beam size. The expression of the ion beam intensity of the beam energy in the plasma focused ion beam is:

[0059]

[0060] Among them, J is the ion flow concentration at the processing position during plasma focused ion beam processing, I is the beam size during plasma focused ion beam processing, σ is the standard deviation, x, y are the corresponding coordinate positions on the processing surface when the processing center position is (0.0); the solution is a proportional relationship and therefore is not involved in the calculation; considering that the ion beam intensity distribution is used in the large beam used in rough processing, there will be obvious side wall tilt when processing difficult-to-process materials such as diamond, and the tilt angle will be proportional to the selected beam size and the μA-level tilt angle is less than 5°. Manual compensation can obtain a rough back tool face 4 contour, which is convenient for subsequent fine finishing.

[0061] S4. Rough and fine-process the front cutting edge 2 of the single crystal diamond tool respectively: Place the upper surface 1 of the material of the single crystal diamond tool vertically upward on the sample stage, fix it according to the emission direction of the electron beam and ion beam in the focused ion beam device, rotate the sample stage around the workbench to 52 degrees, and use angle compensation so that the processing direction of the ion beam is just to use the side wall damage defect to vertically process the upper surface 1 of the material of the single crystal diamond tool, etch a shallow groove at the edge of the processed single crystal diamond tool as a mark for negative front angle processing, and then put the single crystal diamond tool The front cutting surface 2 of the tool is mounted on the auxiliary inclined table with the front cutting surface 2 facing upwards, the purpose is to expand the angle range between the front cutting surface 2 of the single crystal diamond tool and the ion gun, and the auxiliary inclined table is fixedly flipped around the fixed axis T axis rotation direction 8 of the equipment. Specifically, the selection of the flipping degree is related to the selection of the auxiliary inclined table. In the embodiment of the present invention, a 40° inclined table 7 is used. The 40° inclined table 7 makes the material upper surface 1 of the single crystal diamond tool have an angle of 40° with the horizontal plane of the workbench, so it is necessary to flip the specific angle of 18° to obtain the front cutting surface 2 with a negative front angle of 20°; the specific operation angle is as follows Figure 6 As shown, the parameters used are an accelerating voltage of 30 kV and an accelerating current of 15 nA.

[0062] Specifically, the length of the shallow groove is between 50μm-100μm, and the depth is between 0-1μm, and a clear boundary can be observed. Considering the size of the single crystal diamond tool in this embodiment, the distance between the shallow groove and the edge of the cutting edge of the processed single crystal diamond tool is between 150μm-250μm.

[0063] S5. Finishing the side blade of the single crystal diamond tool: fix the lower surface 3 of the single crystal diamond tool material upward on the 40° inclined table 7, ensure that the two side blades of the single crystal diamond tool are parallel to the processing direction of the plasma focused ion beam, and use the small beam of the plasma focused ion beam to fine-tune the position near the cutting edge. Considering the interference problem of rough machining, the selection of the processing area should be slightly wider when fine-tuning the side blade. Considering that the side blade of the tool has a lower impact on the processing, the cutting is mainly the front blade 2 and the back blade 4, but the processing of the side blade can highlight the edge range of the back blade 4 and the front blade 2, so it can be fine-tuned until there is no obvious surface damage. The processing parameters are an acceleration voltage of 30kV and an acceleration current of 60nA. The tool fixation and processing parameters for processing the two side blades are the same.

[0064] S6. Finishing the back face 4 of the single crystal diamond tool: fix the lower surface 3 of the single crystal diamond tool material on the 40° inclined table 7 with it facing upwards. Because it already has a 40° machining inclination angle, a back angle of 6°-8° needs to be machined. Considering that the angle between the direction of the ion beam and the back face 4 of the tool is exactly 2 degrees, the 40° inclined table 7 is flipped 4°-6° around the fixed axis T-axis of the equipment in the rotation direction 8 to obtain a back face 4 with an angle of 6°-8°. Then, a small beam of 60nA and a small beam of 15nA are used to perform primary and secondary machining on the cutting edge of the single crystal diamond tool, respectively, to obtain a single crystal diamond tool with a certain hardness of the cutting edge.

[0065] Furthermore, in addition to ensuring that there are no obvious processing defects during processing, considering that the back blade 4 of the single-crystal diamond tool will directly affect the sharpness of the cutting edge, two small beam processings are used, one with 60nA processing and the second processing with a small beam of 15nA. The edge area with weaker beam energy distribution in the plasma focused ion beam must be processed at a distance of 50nm-100nm from the edge area at the cutting edge. The reason for doing this is that it can avoid processing defects to a limited extent - the inclined side wall can obtain a better processing surface.

[0066] The side cutting edge processing area uses a rectangle, while the back cutting edge 4 processing area needs to draw an arc ring processing area by itself. This is because it is necessary to consider that the drawing function of the focused ion beam equipment can only process conventional patterns: rectangles, circles or triangles. If you want to process unconventional patterns, you need to use plane drawing software to draw a grayscale picture with a black background and a white processing pattern, and import it into the focused ion beam software to process unconventional patterns. Considering that the arc cutting edge needs to be processed, it is necessary to draw a circle with an arc cutting edge. Different complex patterns can be designed for regional processing for different tools. Because the turning tool is processed, a crescent-shaped processing pattern is drawn for edge processing.

[0067] Furthermore, in order to ensure the edge quality of the single-crystal diamond tool, a large beam current of μA level is used for rough machining, and a small beam current of nA level is used for fine machining; in order to ensure the removal efficiency, the acceleration voltage for rough machining and fine machining is 30kV. When processing different materials, the selection of acceleration voltage can be calculated by the SRIM simulation software using the Monte Carlo method to deduce a more appropriate acceleration voltage, with the sputtering yield being the main criterion.

[0068] The following is a further description of a forming method for a single crystal diamond tool based on a focused ion beam according to the present invention in conjunction with an embodiment:

[0069] The forming method of the present invention is used to etch single crystal diamond through a plasma focused ion beam using Xe ions as an ion source. Based on the basic theory of the tool and the requirements for the angle range, a single crystal diamond tool is designed with a cutting edge arc radius of 500 μm, a blunt circle radius of the machined cutting edge of about 0.85 μm, a front cutting face 2 angle of -20°, and a back cutting face 4 angle of 7°.

[0070] The specific operation steps of the forming method for a single crystal diamond tool based on a focused ion beam of the present invention for processing a single crystal diamond tool with a cutting edge of 500 μm are as follows:

[0071] S1. Etching the single crystal diamond tool: etching the front cutting surface 2, the back cutting surface 4 and the side cutting surface of the single crystal diamond tool using a plasma focused ion beam with Xe ions as an ion source.

[0072] S2, side cutting edge of rough machining single crystal diamond tool: Figure 2a As shown, the upper surface 1 of the material of the single crystal diamond tool obtained by S1 is facing upward and fixed on the sample stage. The parameters selected are the maximum beam current of 2.5μA that the Xe ion equipment can achieve, and the acceleration voltage is 30kV. Rough processing is performed from the front side of the single crystal diamond tool to avoid interference between the shutter (shutter - a device in the vacuum chamber) and the tool handle. The ion gun and the electron gun are at an angle of 52°, and a side tool surface with a stepped plane but able to reflect the contour is obtained.

[0073] S3, Rough machining of single crystal diamond tool back face 4: Figure 2b As shown, according to the material and processing speed of the single crystal diamond tool, the angle between the plasma focused ion beam and the workbench is adjusted. Considering that the energy distribution will cause processing defects when the beam is large - inclined side walls, it is necessary to manually compensate 1°-4° so that the processing direction of the plasma focused ion beam is 88° with the two directions of the processing surface instead of vertical processing. When processing the back face 4 of the single crystal diamond tool, it is necessary to flip it around the fixed T-axis rotation direction 8 to 45° so that the back face 4 and the side face have a back angle of 7°.

[0074] S4, respectively, rough machining and finishing of the single crystal diamond tool has a rake face with a negative rake angle of 20° 2: Figure 2cAs shown, the upper surface 1 of the material of the single crystal diamond tool is placed vertically upward on the sample stage, and the emission direction of the electron beam and the ion beam in the focused ion beam device is fixed, and the sample stage is rotated around the workbench to 52 degrees, and a shallow groove is etched at a distance of 200μm from the edge of the cutting edge of the processed single crystal diamond tool as a mark for negative rake angle processing, and then the single crystal diamond tool front blade 2 is mounted on the auxiliary ramp with the front blade face 2 facing upward, and the auxiliary ramp is fixedly flipped 20° around the fixed axis T axis of the device in the rotation direction 8, and a front blade face 2 with a negative rake angle of 18° is obtained; the specific schematic diagram is shown as follows Figure 6 As shown, the acceleration voltage parameters used are 30 kV and the acceleration current parameters are 15 nA.

[0075] S5, such as Figure 6 As shown in the figure, the finishing single crystal diamond tool has a side cutting edge with a 7° inclination angle: Figure 2d As shown, the lower surface 3 of the single crystal diamond tool material is fixed upward on a 40° inclined table 7, the rotation angle is 45°, the processing area is rectangular, and the small beam of plasma focused ion beam is used to fine-tune the position near the cutting edge. Considering the interference problem of rough machining, the selection of the processing area when fine-tune the side tool surface should be slightly wider, and fine-tune until there is no obvious surface damage. The processing parameters are an acceleration voltage of 30kV and an acceleration current of 60nA, and the tool fixing and processing parameters for processing the two side tool surfaces are the same.

[0076] S6, finishing single crystal diamond tool with 7° back angle flank 4: Figure 2e As shown, the lower surface 3 of the single crystal diamond tool material is fixed upward on a 40° inclined table 7, and the 40° inclined table 7 is turned 4°-6° around the fixed axis T axis rotation direction 8 of the equipment. The processing area is a drawn arc ring pattern, and a back tool face 4 with an angle of 6°-8° is obtained; then, a small beam of 60nA and a small beam of 15nA are used to perform primary and secondary processing on the edge of the single crystal diamond tool, respectively, to obtain a single crystal diamond tool with a certain hardness edge, as shown in FIG. Figure 3 shown.

[0077] Fix the tool on an inclined table for measurement, measure the area near the tool edge with a white light interferometer, fit the contour near the tool edge, and measure the radius of the fitting arc at the edge through the fitting curve, which is the radius of the tool processing edge. Figure 4 As shown, the gray fitting circle is the cutting edge, and the curves on both sides are the surface contours of the front cutting edge 2 and the back cutting edge 4. The unevenness on the right side is caused by the uneven thickness of the Pt coating on the tool surface. The radius of the gray fitting circle is the cutting edge radius of the tool. The cutting edge radius of the tool is measured to be 0.85μm.

[0078] Nanotech 450UPL ultra-precision machine tool was used for cutting. The cutting material selected was common Cu, which was a square sheet with a cross-section of 2 cm and a side length of 3 mm. The entire plane was processed by a tool processed by P-FIB (a focused ion beam device with four ion sources). The performance of the tool was evaluated by observing the surface quality and tool wear. The feed speed was 2 mm / min, the cutting depth was 2 μm, and the spindle speed was 2000 r / min. Figure 5a This is the measurement result of the surface of the Cu surface processed by the diamond tool obtained under P-FIB under the white light interferometer. As shown in Figure 5, the processed surface is good, without scratches, burrs and other defects, and the surface roughness can reach 6nm. Figure 5b This is the wear condition of the diamond tool after 6 surface processing. The edge wear of the tool at the location with larger edge wear is observed under SEM (scanning electron microscope). It can be seen from Figure 5 that the wear is in line with the rules and the size is only less than 10μm. At this time, the cutting distance reaches 2400mm, which is enough to prove that the service life of the diamond tool can meet most of the processing, and there will be no problem of frequent replacement or maintenance of the tool.

[0079] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A forming method for a single crystal diamond tool based on a focused ion beam, characterized in that: The following steps are involved: S1. Etching the single crystal diamond tool: etching the rake face, flank face and side face of the single crystal diamond tool using a plasma focused ion beam with Xe ions as an ion source; S2. Rough machining of the side cutting edge of the single crystal diamond tool: fix the single crystal diamond tool obtained in S1 on a sample stage with its upper surface facing upward, and use a plasma focused ion beam to perform rough machining on the side cutting edge of the single crystal diamond tool to remove material, thereby obtaining a side cutting edge with a step-shaped profile defect; S3. Rough machining of the back face of the single crystal diamond tool: According to the characteristics of the single crystal diamond tool, the angle between the plasma focused ion beam and the workbench is adjusted. Considering that the energy distribution will cause a machining defect - inclined side wall when the beam current is large, manual compensation is performed so that the back face to be machined and the side face after rough machining have a back angle of 6°-8°. The expression of the ion beam intensity of the beam energy in the plasma focused ion beam is: Wherein, J is the ion flow concentration at the processing position during plasma focused ion beam processing, I is the beam size during plasma focused ion beam processing, σ is the standard deviation, and x and y are the corresponding coordinate positions on the processing surface when the processing center position is (0.0); S4. Rough-machining and fine-machining the front cutting edge of the single crystal diamond tool respectively: placing the upper surface of the material of the single crystal diamond tool vertically upward on the sample table, rotating the sample table around the workbench to 52 degrees, etching a shallow groove at the edge of the cutting edge of the processed single crystal diamond tool, and then mounting the single crystal diamond tool with the front cutting edge facing upward on the auxiliary ramp, and turning the auxiliary ramp around the fixed axis T of the equipment at a certain angle to obtain a front cutting edge with a negative front angle of 20°; S5. Finishing the side cutting edge of the single crystal diamond tool: Fix the upper surface of the single crystal diamond tool material downward on the auxiliary inclined table, and use the nA-level small beam flow of the plasma focused ion beam to fine-tune the position of the cutting edge until there is no obvious surface damage. In the process, the step defects generated by the rough machining will be neutralized to improve the efficiency; S6. Finishing the back face of the single crystal diamond tool: fix the single crystal diamond tool material with the upper surface facing downward on the auxiliary ramp, and flip the auxiliary ramp 4°-6° around the fixed axis T of the equipment to obtain a back face with an angle of 6°-8°; then use a small beam of 60nA and a small beam of 15nA to perform primary and secondary processing on the cutting edge of the single crystal diamond tool respectively to obtain a single crystal diamond tool with a certain hardness cutting edge.

2. The forming method for single crystal diamond tool based on focused ion beam according to claim 1, characterized in that: In step S1, the plasma focused ion beam is based on the sputtering yield of Sigmund theory, and the expression of the linear chain collision model of the sputtering yield of Sigmund theory is: Among them, M1 and M2 are the relative atomic masses of the incident ions and the target material, Z1 and Z2 are the atomic numbers of the incident ions and the solid target material atoms, and Y is the sputtering yield. E s is the surface binding energy of the solid target, S n is the nucleus stopping cross section, θ is the incident angle of the ion beam, E represents the energy generated, and ε is the reduced energy, that is, the ratio of the backscattered electron energy to the incident electron energy.

3. The forming method for a single crystal diamond tool based on a focused ion beam according to claim 1, characterized in that: In step S2, the expression for removing material in the rough machining is: Wherein, W is the removal amount of the single crystal diamond tool, m is the relative atomic mass of the atoms of the single crystal diamond tool, I is the beam current of the focused ion beam, and t is the sputtering time of the plasma focused ion beam.

4. The forming method for single crystal diamond tool based on focused ion beam according to claim 1, characterized in that: In step S3, the manual compensation angle is 1°-4°.

5. The forming method for single crystal diamond tool based on focused ion beam according to claim 1, characterized in that: In step S4, the shallow groove has a length of 50 μm-100 μm, a depth of 0 μm-1 μm, and a distance between the shallow groove and the edge of the cutting edge of the processed single crystal diamond tool is 150 μm-250 μm.

6. The forming method for single crystal diamond tool based on focused ion beam according to claim 1 or 5, characterized in that: In step S4, the inclination angle of the auxiliary ramp is 40°.

7. The forming method for single crystal diamond tool based on focused ion beam according to claim 1, characterized in that: In step S6, when the secondary processing is performed with a small beam current of 15 nA, the edge area with weaker beam energy distribution in the plasma focused ion beam needs to be processed at a distance of 50 nm-100 nm from the edge area at the cutting edge.

8. The forming method for single crystal diamond tool based on focused ion beam according to claim 1, characterized in that: A large beam current of μA level is selected for rough machining, and a small beam current of nA level is selected for fine machining. The acceleration voltage of the rough machining and the fine machining is 30 kV.

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